Been suggested soooooo many times
This is a idea that has been asked and asked and asked for many times.
This spell would be basically useless because of two reasons. First, this would have no effect on your attacking. If you're attacking a person in basic PvP, not war, there's no reason to know their traps. Even if you were attacking in war, knowing where there giant bombs, teslas, air bombs, and spring traps would have no effect on your attacking, unless your opponent is stupid and you can easily trigger their traps with one troop... Second, knowing what's in the clan castle wouldn't exactly help. In normal attacking, you can just lure than clan castle with two or three giants, and boom! you know what's in the clan castle. Even if it was an unlurable design, knowing what was in the clan castle wouldn't help, you'll find out eventually. Even in war, the spell is useless because it doesn't matter what troops in it (except for wallbreakers, healers, or goblins), if it's not lured properly it's going to ruin your attack. Also, you can guess what's in the clan castle. It's always, unless you're in a non-serious war clan, going to be witches, archers, wizards, valks, or balloons.
Idea is not needed